Vehicle

ABSTRACT

A vehicle includes a high-voltage system circuit including a high-voltage battery; a low-voltage system circuit including a low-voltage battery and an updater; a DC-DC converter coupled between the two circuits; and a controller that controls the two circuits and the DC-DC converter. The updater updates a program of an update-target device. The DC-DC converter reduces in voltage output electric power of the high-voltage battery and then supplies the electric power to the low-voltage system circuit. The controller determines whether the update-target device is a certain device relating to electric power supply from the high-voltage battery. If the update-target device is the certain device, the low-voltage battery is charged with the output electric power of the high-voltage battery, the certain device stops operating, and the updater updates the program of the certain device by using the output electric power of the low-voltage battery.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNo. 2020-162152 filed on Sep. 28, 2020, the entire contents of which arehereby incorporated by reference.

BACKGROUND

The disclosure relates to a vehicle.

In recent years, there has been proposed a technique for updating aprogram of an electronic control unit that controls an engine, a motor,and other vehicle-mounted devices installed in a vehicle. Hereinafter,updating a program is also referred to as reprogramming.

Reprogramming is commonly performed when a vehicle and an engine arestopped. Thus, reprogramming is performed by using electric power storedin a battery such as a 12V accessory battery (low-voltage battery) (see,for example, Japanese Unexamined Patent Application Publication No.2017-166434).

SUMMARY

An aspect of the disclosure provides a vehicle including a high-voltagesystem circuit, a low-voltage system circuit, a direct current (DC)-DCconverter, and a controller. The high-voltage system circuit includes ahigh-voltage battery. The low-voltage system circuit includes alow-voltage battery and an updater. The low-voltage battery has a loweroutput voltage than the high-voltage battery. The updater is configuredto update a program of an update-target device by using electric powersupplied from the low-voltage battery or the high-voltage battery. TheDC-DC converter is coupled between the high-voltage system circuit andthe low-voltage system circuit and is capable of reducing in voltageoutput electric power of the high-voltage battery and supplying theelectric power reduced in voltage to the low-voltage system circuit. Thecontroller is configured to control the high-voltage system circuit, thelow-voltage system circuit, and the DC-DC converter. The controller isconfigured to determine whether the update-target device is a certaindevice relating to electric power supply from the high-voltage batteryto the low-voltage system circuit. In a case where the update-targetdevice is the certain device, the controller is configured to cause theDC-DC converter to reduce the output electric power of the high-voltagebattery and to supply the reduced electric power to the low-voltagesystem circuit so as to charge the low-voltage battery, configured tocause the certain device to stop operating after the low-voltage batteryis charged, and configured to cause the updater to update the program ofthe certain device by using the output electric power of the low-voltagebattery.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification. The drawings illustrate an exampleembodiment and, together with the specification, serve to explain theprinciples of the disclosure.

FIG. 1 is a functional block diagram for describing a vehicle inaccordance with an embodiment;

FIG. 2 is a block diagram illustrating an electric/electronic systemcircuit that is controlled by a control device in accordance with theembodiment;

FIGS. 3A and 3B are diagrams for describing how a target state of charge(SOC) of a high-voltage battery is controlled by a high-voltage batterycontroller in accordance with the embodiment;

FIG. 4 is a diagram illustrating a reprogramming confirmation screen inaccordance with the embodiment;

FIGS. 5A and 5B are flowcharts for describing a control processperformed in relation to reprogramming in the vehicle in accordance withthe embodiment; and

FIG. 6 is a flowchart for describing a reprogramming operation controlprocess performed in the vehicle in accordance with the embodiment.

DETAILED DESCRIPTION

In recent years, time taken for reprogramming tends to increase becauseof an increase in a program capacity or the like. If the time taken forreprogramming increases, electric power used for reprogrammingincreases. Thus, if electric power is not sufficiently stored in abattery at the time of reprogramming, updating of a program may beaborted because of a deficiency of electric power.

Accordingly, when a charge level of a 12V accessory battery (low-voltagebattery) is deficient, reprogramming is conceivably performed byreducing output electric power of a high-voltage battery for driving amotor used by a vehicle to travel and by using the reduced electricpower as electric power for reprogramming. However, there is room forimprovement of the method of using, as the electric power forreprogramming, the electric power supplied from the high-voltage batteryinstead of the 12V accessory battery in that it is difficult to performreprogramming of a device relating to electric power supply from thehigh-voltage battery to a low-voltage system circuit.

Accordingly, it is desirable to provide a vehicle capable of reducingthe likelihood of updating of a program being aborted because of adeficiency of electric power and capable of performing reprogramming ofa device relating to electric power supply from a high-voltage batteryto a low-voltage system circuit.

In the following, an embodiment of the disclosure is described in detailwith reference to the accompanying drawings. Note that the followingdescription is directed to an illustrative example of the disclosure andnot to be construed as limiting to the disclosure. Factors including,without limitation, numerical values, shapes, materials, components,positions of the components, and how the components are coupled to eachother are illustrative only and not to be construed as limiting to thedisclosure. Further, elements in the following example embodiment whichare not recited in a most-generic independent claim of the disclosureare optional and may be provided on an as-needed basis. The drawings areschematic and are not intended to be drawn to scale. Throughout thepresent specification and the drawings, elements having substantiallythe same function and configuration are denoted with the same numeralsto avoid any redundant description.

FIG. 1 is a functional block diagram for describing a vehicle 1 inaccordance with an embodiment. The vehicle 1 including an engine 10 anda motor 12 as driving sources for traveling is presented as an example.The vehicle 1 according to the embodiment is, for example, a so-calledparallel hybrid vehicle. The engine 10 is mainly used as a motive powersource to cause an output shaft 14 to rotate. The motor 12, which is athree-phase alternating current (AC) motor, is also a motive powersource but merely plays a role of assisting the engine 10. A drive modein which the engine 10 and the motor 12 are jointly used is referred toas a joint use mode.

At the time of low-speed traveling in which the speed of the engine 10is low such as at the time when the vehicle 1 starts traveling or startsaccelerating, power or torque of the engine 10 is small. Thus, a clutch16 is released, and the drive mode is switched from the joint use modeto an electric vehicle (EV) mode in which the motor 12 alone is used asthe motive power source. The drive mode is switchable from the joint usemode to the EV mode in accordance with a traveling state at the timesother than the time when the vehicle 1 starts traveling or startsaccelerating.

An endless member such as a belt 20 extends around an integrated startergenerator (ISG) 18 and the output shaft 14 of the engine 10, so that theISG 18 is coupled to the engine 10. Consequently, the ISG 18 functionsas a starter motor that transfers motive power to the engine 10 toassist the engine 10 in starting. The ISG 18 also functions as analternator that regenerates electric power. Conceivable timings when theengine 10 is started include not only a timing when the vehicle 1 startstraveling but also various timings such as a timing when the drive modeis switched from the EV mode to the joint use mode and a timing when theengine 10 in a non-idling state is restarted.

A control device 22 includes, for example, semiconductor integratedcircuits including a central processing unit (CPU), a read-only memory(ROM) that stores a program or the like, and a random access memory(RAM) that serves as a work area. The control device 22 controls theentire vehicle 1 or various devices installed in the vehicle 1. Forexample, the control device 22 controls each component of anelectric/electronic system circuit that includes a high-voltage battery32 (see FIG. 2) and a low-voltage battery 42 (see FIG. 2), which will bedescribed later.

The control device 22 is coupled to a wireless communication device 50 a(see also FIG. 2) and is capable of transmitting and receiving variouskinds of data to and from an external device via the wirelesscommunication device 50 a. The wireless communication device 50 a iscapable of wirelessly communicating with a data distribution center 102via a network 100. The data distribution center 102 has a function ofdistributing reprogramming information for use in updating of a programfor controlling an update-target device 44 (see FIG. 2 described later)installed in the vehicle 1. The reprogramming information includes, forexample, information for designating the update-target device 44 forwhich reprogramming is performed, and information on update data for usein reprogramming.

The control device 22 includes an automotive navigation systemcontroller 52 a (see FIG. 2) described later. The automotive navigationsystem controller 52 a enables various kinds of information such as mapinformation to be displayed on a display 24 coupled to the controldevice 22.

FIG. 2 is a block diagram illustrating the electric/electronic systemcircuit that is controlled by the control device 22 in accordance withthe embodiment. As illustrated in FIG. 2, the electric/electronic systemcircuit installed in the vehicle 1 includes a high-voltage systemcircuit 30, a low-voltage system circuit 40, and a direct current(DC)-DC converter 60. The high-voltage system circuit 30 includes thehigh-voltage battery 32 and a high-voltage relay 34. The high-voltagerelay 34 is a relay device that switches on and off the electricalcoupling of the high-voltage battery 32 in the high-voltage systemcircuit 30.

The low-voltage system circuit 40 includes the low-voltage battery 42,the update-target device 44, an updater 46, and a vehicle load 48. Thelow-voltage battery 42 is a rechargeable battery having a lower outputvoltage than the high-voltage battery 32. The low-voltage battery 42 is,for example, a 12V accessory battery and supplies relatively-low-voltage(for example, 12V) DC electric power to various vehicle-mounted devices(accessories) installed in the vehicle 1. The updater is a programupdating tool that performs updating of a program (reprogramming) of theupdate-target device 44 in accordance with an instruction of the controldevice 22. The updater 46 performs reprogramming of the update-targetdevice by using electric power supplied from the low-voltage battery 42or the high-voltage battery 32. Examples of the vehicle load 48 includeelectrical loads such as a door-mirror motor (not illustrated), apower-window motor (not illustrated), and a radiator-fan motor (notillustrated), for example.

In one example, the update-target device 44 is, for example, an enginecontroller 10 a, a motor controller 12 a, a high-voltage batterycontroller 32 a, a high-voltage relay controller 34 a, a low-voltagebattery controller 42 a, the wireless communication device 50 a, theautomotive navigation system controller 52 a, an ignition power supply(IG power supply) controller 54 a, or a DC-DC converter controller 60 a.The engine controller 10 a controls the engine 10. The motor controller12 a controls the motor 12. The high-voltage battery controller 32 acontrols the high-voltage battery 32. The high-voltage relay controller34 a controls the high-voltage relay 34. The low-voltage batterycontroller 42 a controls the low-voltage battery 42. The wirelesscommunication device 50 a wirelessly communicates with the datadistribution center 102 via the network 100. The automotive navigationsystem controller 52 a controls an automotive navigation system. The IGpower supply controller 54 a controls an IG power supply of the vehicle1 to be in an IG-ON (READY-ON) or IG-OFF (READY-OFF) state on the basisof a user operation. The DC-DC converter controller 60 a controlsoperation of the DC-DC converter 60.

The DC-DC converter 60 is coupled between the high-voltage systemcircuit 30 and the low-voltage system circuit 40. The DC-DC converter 60is capable of reducing in voltage output electric power of thehigh-voltage battery 32 of the high-voltage system circuit 30 and ofsupplying the electric power reduced in voltage to the low-voltagebattery 42, the update-target device 44, the updater 46, the vehicleload 48, etc. of the low-voltage system circuit 40. That is, the DC-DCconverter 60 can reduce a voltage of output electric power of thehigh-voltage battery 32 of the high-voltage system circuit 30 and supplythe electric power with reduced voltage to the low-voltage battery 42,the update-target device 44, the updater 46, the vehicle load 48, etc.of the low-voltage system circuit 40.

The high-voltage battery controller 32 a sets a target state-of-charge(SOC) range, that is, an upper-limit value and a lower-limit value, forthe high-voltage battery 32, and controls charging and discharging ofthe high-voltage battery 32 in accordance with this target SOC range.

FIGS. 3A and 3B are diagrams for describing how the target SOC of thehigh-voltage battery 32 is controlled by the high-voltage batterycontroller 32 a. As illustrated in FIG. 3A, at normal time when noreprogramming is scheduled, the high-voltage battery controller 32 asets, as the target SOC range, a normal SOC upper-limit value and anormal SOC lower-limit value. For example, the normal SOC upper-limitvalue may be set to 90% of the fully charged state of the high-voltagebattery 32 which is represented as 100%. For example, the normal SOClower-limit value may be set to 50% of the fully charged state of thehigh-voltage battery 32 which is represented as 100%. The normal SOCupper-limit and lower-limit values are not limited to these specificexamples.

In response to the wireless communication device 50 a receivingreprogramming information from the data distribution center 102 via thenetwork 100 and reprogramming being scheduled, the high-voltage batterycontroller 32 a changes the target SOC lower-limit value of thehigh-voltage battery 32 to a value (scheduled reprogramming preparationvalue) that is higher than the normal lower-limit value (normal SOClower-limit value). The high-voltage battery controller 32 a sets theSOC upper-limit value to the normal SOC upper-limit value.

In one example, when the wireless communication device 50 a receivesreprogramming information from the data distribution center 102 via thenetwork 100, the high-voltage battery controller 32 a determines thatreprogramming is scheduled. The high-voltage battery controller 32 acalculates electric power used for reprogramming of the update-targetdevice 44 (hereinafter, also referred to as “electric power forreprogramming”) on the basis of the received reprogramming information.

In one example, the reprogramming information includes various kinds ofinformation such as a program capacity for the update-target device 44,a write speed of writing the update program to the update-target device44, electric power consumption per unit time during reprogramming, and acommunication speed between the updater 46 and the update-target device44, for example. The high-voltage battery controller 32 a calculates theelectric power for reprogramming on the basis of all or some of thesevarious kinds of information.

On the basis of the calculated electric power for reprogramming, thehigh-voltage battery controller 32 a changes the target SOC lower-limitvalue of the high-voltage battery 32 to the scheduled reprogrammingpreparation value that is higher than the normal value. For example, thehigh-voltage battery controller 32 a sets the target SOC lower-limitvalue of the high-voltage battery 32 to the scheduled reprogrammingpreparation value (for example, 70% of the fully charged state) that ishigher than the normal value (for example, 50% of the fully chargedstate). In some embodiments, the target SOC lower-limit value (scheduledreprogramming preparation value) is set to a larger value as thecalculated electric power for reprogramming becomes larger.Consequently, the high-voltage battery 32 is sufficiently charged and acharge level higher than or equal to the electric power forreprogramming can be ensured. Thus, a deficiency of electric powerduring reprogramming is successfully avoided.

In the embodiment, the high-voltage battery controller 32 a calculatesthe electric power for reprogramming of the update-target device 44 onthe basis of the reprogramming information.

The high-voltage battery controller 32 a changes the target SOClower-limit value of the high-voltage battery 32 on the basis of thecalculated electric power for reprogramming. However, the embodiment ofthe disclosure is not limited to this. For example, in response to thewireless communication device 50 a receiving reprogramming informationfrom the data distribution center 102 via the network 100 andreprogramming being scheduled, the high-voltage battery controller 32 amay set a predetermined SOC lower-limit value as the target SOClower-limit value (scheduled reprogramming preparation value) of thehigh-voltage battery 32. For example, the SOC lower-limit value servingas the scheduled reprogramming preparation value may be set in advanceto 70% of the fully charged state of the high-voltage battery 32 whichis represented as 100%.

Alternatively, the reprogramming information may include electric powerinformation on the electric power used for reprogramming of theupdate-target device 44. In this case, the high-voltage batterycontroller 32 a changes the target SOC lower-limit value of thehigh-voltage battery 32 on the basis of the electric power information.

The high-voltage battery controller 32 a then changes the target SOClower-limit value of the high-voltage battery 32 to the scheduledreprogramming preparation value. The high-voltage battery 32 is chargedto a charge level that is higher than or equal to the scheduledreprogramming preparation value. In response to a user operation (IG-OFFoperation) for setting the vehicle 1 to READY-OFF performed in a statein which reprogramming is scheduled, the updater 46 checks the chargelevels of the high-voltage battery 32 and the low-voltage battery 42.

FIG. 4 is a diagram illustrating a reprogramming confirmation screen 24a in accordance with the embodiment. If the charge level of thelow-voltage battery 42 is higher than or equal to the electric powerlevel used for reprogramming of the update-target device 44 and thusreprogramming of the update-target device 44 can be performed by usingthe low-voltage battery 42, or if the charge level of the high-voltagebattery 32 is higher than or equal to the scheduled reprogrammingpreparation value, the automotive navigation system controller 52 acauses the reprogramming confirmation screen 24 a to be displayed on thedisplay 24 as illustrated in FIG. 4. The reprogramming confirmationscreen 24 a asks for the user's confirmation to perform reprogramming.

In the reprogramming confirmation screen 24 a, for example, a warningmessage “Once reprogramming starts, the vehicle 1 is not usable untilreprogramming ends” and button images that allow the user to selectwhether to confirm reprogramming (Yes or No) are displayed.

If the user presses the “Yes” button in the reprogramming confirmationscreen 24 a to confirm reprogramming, a reprogramming operation starts.On the other hand, if the user presses the “No” button in thereprogramming confirmation screen 24 a to reject reprogramming or ifneither the “Yes” button nor the “No” button is pressed by the user inthe reprogramming confirmation screen 24 a, the reprogramming operationdoes not start.

In response to the start of the reprogramming operation, the updater 46performs reprogramming of the update-target device 44 by using electricpower of the low-voltage battery 42 if reprogramming of theupdate-target device 44 can be performed by using the low-voltagebattery 42.

On the other hand, if the charge level of the low-voltage battery 42 isnot sufficient and thus reprogramming of the update-target device 44 isunable to be performed by using the low-voltage battery 42, in order toperform reprogramming by using the high-voltage battery 32, thehigh-voltage relay controller 34 a brings the high-voltage relay 34 intoa coupled state to enable electric power of the high-voltage battery 32to be output to the DC-DC converter 60. The DC-DC converter controller60 a causes the DC-DC converter 60 to start operating, to reduce involtage electric power output from the high-voltage battery 32, and tosupply the electric power reduced in voltage to the low-voltage systemcircuit 40.

At this time, the updater 46 determines whether the update-target device44 subjected to reprogramming is a certain device used for supplyingelectric power from the high-voltage battery 32. Examples of such acertain device include the high-voltage battery controller 32 a, theDC-DC converter controller 60 a, and the high-voltage relay controller34 a, for example.

If the update-target device 44 subjected to reprogramming is not thecertain device used for supplying electric power from the high-voltagebattery 32, the updater 46 performs reprogramming of the update-targetdevice 44 by using electric power supplied from the high-voltage battery32 to the low-voltage system circuit 40. In response to the end ofreprogramming, the DC-DC converter controller 60 a causes the DC-DCconverter 60 to stop operating and the high-voltage relay controller 34a breaks the coupling of the high-voltage relay 34.

If the update-target device 44 subjected to reprogramming is the certaindevice used for supplying electric power from the high-voltage battery32, reprogramming of the update-target device 44 by the updater 46 isnot performed in a state in which the low-voltage system circuit 40 isbeing supplied with electric power from the high-voltage battery 32.Thus, in the embodiment, the update-target device 44 (certain device) orthe like is temporarily used to supply electric power to the low-voltagebattery 42 from the high-voltage battery 32 through the DC-DC converter60 and to sufficiently charge the low-voltage battery 42. After chargingof the low-voltage battery 42 ends, electric power supply from thehigh-voltage battery 32 is stopped and the update-target device 44(certain device) is caused to stop operating. Then, the updater 46performs reprogramming of the update-target device 44 (certain device)by using electric power supplied from the low-voltage battery 42.

In one example, the low-voltage battery controller 42 a charges thelow-voltage battery 42 until the charge level of the low-voltage battery42 becomes equal to a level with which reprogramming of theupdate-target device 44 can be performed by using the low-voltagebattery 42. At this time, the low-voltage battery controller 42 a candetermine the charge level of the low-voltage battery 42 on the basis ofthe electric power used for reprogramming of the update-target device 44which is calculated by the high-voltage battery controller 32 a. Theconfiguration is not limited to such an example. The low-voltage batterycontroller 42 a may charge the low-voltage battery 42 to a predeterminedcharge level set in advance. For example, this predetermined chargelevel may be set in advance to 90% of the fully charged state of thelow-voltage battery 42 which is represented as 100%.

In response to the completion of charging of the low-voltage battery 42,the DC-DC converter controller 60 a ends the operation of the DC-DCconverter 60 and the high-voltage relay controller 34 a breaks thecoupling of the high-voltage relay 34. Then, the updater 46 performsreprogramming of the update-target device 44 by using electric power ofthe low-voltage battery 42 that has been charged.

Control Method

FIGS. 5A and 5B are flowcharts for describing a control processperformed in relation to reprogramming in the vehicle 1 in accordancewith the embodiment.

As illustrated in FIG. 5A, in response to a user operation, the IG powersupply controller 54 a of the control device 22 switches on the IG powersupply and controls the vehicle 1 to be in the READY-ON (IG-ON) state(step S101).

The control device 22 wirelessly communicates with the data distributioncenter 102 via the wireless communication device 50 a and checks whetherreprogramming data yet to be received by the vehicle 1 of interest ispresent in reprogramming data distributed from the data distributioncenter 102 (step S103). The reprogramming data is data including updatedata for updating a program of the update-target device 44. The datadistribution center 102 distributes reprogramming information includingthe reprogramming data for performing reprogramming to each vehicle 1via the network 100 when it is desirable to perform reprogramming of theupdate-target device 44.

If it is determined in S103 that yet-to-be-received reprogramming datais not present (NO in step S103), the high-voltage battery controller 32a of the control device 22 determines whether a reprogramming datareception flag is on (step S105). If the reprogramming data receptionflag is on, the vehicle 1 of interest has already received reprogrammingdata but reprogramming is yet to be performed in accordance with thereprogramming data. Thus, the reprogramming data reception flagindicates a state in which reprogramming is to be performed(reprogramming is scheduled).

If it is determined in 5105 that the reprogramming data reception flagis off (NO in step S105), reprogramming is not to be performed. Thus,the high-voltage battery controller 32 a sets the SOC lower-limit andupper-limit values of the high-voltage battery 32 to the normal values(step S107). As a result of this, the high-voltage battery 32 ischarged, for example, during traveling of the vehicle 1 thereafterwithin the normal target SOC range (see FIG. 3A).

The IG power supply controller 54 a of the control device 22 thencontrols the vehicle 1 to be in the READY-OFF (IG-OFF) state in responseto a user operation (step S109). The control process then ends.

On the other hand, if it is determined in step S105 that thereprogramming data reception flag is on (YES in step S105), the processproceeds to S117 (described below).

If it is determined in step S103 that the yet-to-be-receivedreprogramming data is present and the reprogramming data is to bereceived from the data distribution center 102 (YES in step S103), thecontrol device 22 receives reprogramming information including thereprogramming data from the data distribution center 102 via the network100 and the wireless communication device 50 a (step S111).

The high-voltage battery controller 32 a of the control device 22calculates electric power used for reprogramming of the update-targetdevice 44 on the basis of the reprogramming information received fromthe data distribution center 102 (step S113), and sets the reprogrammingdata reception flag on (step S115). That is, in response to the wirelesscommunication device 50 a receiving the reprogramming data, thereprogramming data reception flag is set on and reprogramming isscheduled. The reprogramming data reception flag is not set off untilreprogramming is completed.

If it is determined in step S105 that the reprogramming data receptionflag is on (YES in step S105) or if the reprogramming data receptionflag is set on in step S115, the high-voltage battery controller 32 a ofthe control device 22 determines that reprogramming is scheduled. Thehigh-voltage battery controller 32 a of the control device 22 thenchanges the set target SOC lower-limit value of the high-voltage battery32 to the scheduled reprogramming preparation value that is higher thanthe normal value on the basis of the calculated electric power used forreprogramming of the update-target device 44 and sets the SOCupper-limit value to the normal value (step S117). As a result of this,the high-voltage battery 32 is charged, for example, during traveling ofthe vehicle 1 thereafter within a special target SOC range set whenreprogramming is scheduled (see FIG. 3B).

For example, in the case where the vehicle 1 stops thereafter, the IGpower supply controller 54 a of the control device 22 controls thevehicle 1 to be in the READY-OFF (IG-OFF) state in response to a useroperation (step S119).

The control device 22 checks the charge level of the low-voltage battery42 and determines whether the charge level of the low-voltage battery 42is higher than or equal to the electric power level used forreprogramming of the update-target device 44, that is, whetherreprogramming can be performed by using the low-voltage battery 42 (stepS121).

If it is determined that reprogramming is not to be performed by usingthe low-voltage battery 42 (NO in step S121), the control device 22checks the charge level of the high-voltage battery 32 and determineswhether the charge level (actual SOC) of the high-voltage battery 32 ishigher than or equal to the scheduled reprogramming preparation value(target SOC lower-limit value) (step S123).

If it is determined that the charge level of the high-voltage battery 32is higher than or equal to the scheduled reprogramming preparation value(YES in step 5123) or if it is determined that reprogramming can beperformed by using the low-voltage battery 42 (YES in step S121), theautomotive navigation system controller 52 a of the control device 22causes the reprogramming confirmation screen 24 a (see FIG. 4) to bedisplayed on the display 24 (step S125).

The control device 22 then determines whether the “Yes” button isoperated by the user in the reprogramming confirmation screen 24 a (stepS127). If it is determined that the “Yes” button is operated in thereprogramming confirmation screen 24 a and reprogramming is confirmed bythe user (YES in step S127), the control device 22 performs areprogramming operation control process (step S200) by using the updater46. The reprogramming operation control process (step S200) will bedescribed later. In response to the end of the reprogramming operationcontrol process (step S200), the control device 22 sets thereprogramming data reception flag off. The process then ends.

On the other hand, if the “No” button is operated in the reprogrammingconfirmation screen 24 a in step S127 or if neither the “Yes” button northe “No” button is operated by the user in the reprogrammingconfirmation screen 24 a (NO in step S127), the control device 22 endsthe process without performing the reprogramming operation. If it isdetermined in step S123 that the charge level of the high-voltagebattery 32 is lower than the scheduled reprogramming preparation value(NO in step S123), the control device 22 ends the process withoutperforming the reprogramming operation.

Reprogramming Operation Control Process

FIG. 6 is a flowchart for describing the reprogramming operation controlprocess (step S200 in FIG. 5B) performed in the vehicle 1 in accordancewith the embodiment.

As illustrated in FIG. 6, the control device 22 first checks the chargelevel of the low-voltage battery 42 and determines whether the chargelevel of the low-voltage battery 42 is higher than or equal to theelectric power level used for reprogramming of the update-target device44, that is, whether reprogramming can be performed by using thelow-voltage battery 42 (step S201).

If it is determined that reprogramming is not to be performed by usingthe low-voltage battery 42 (NO in step S201), the high-voltage relaycontroller 34 a of the control device 22 brings the high-voltage relay34 into a coupled state (step S203). The DC-DC converter controller 60 acauses the DC-DC converter 60 to start operating, to reduce in voltagethe electric power output from the high-voltage battery 32, and tosupply the electric power reduced in voltage to the low-voltage systemcircuit 40 (step S205). As a result of this, the low-voltage battery 42can be charged by using electric power supplied from the high-voltagebattery 32. Further, in the low-voltage system circuit 40, reprogrammingof the update-target device 44 can be performed by using electric powersupplied from the high-voltage battery 32.

The control device 22 determines whether the update-target device 44subjected to reprogramming is a certain device used for supplyingelectric power from the high-voltage battery 32 (step S207). In oneexample, such a certain device is, for example, the high-voltage batterycontroller 32 a, the DC-DC converter controller 60 a, or the like asdescribed above.

If it is determined that the update-target device 44 subjected toreprogramming is not the certain device used for supplying electricpower from the high-voltage battery 32, the control device 22 instructsthe updater 46 to perform reprogramming. The updater 46 startsreprogramming of the update-target device 44 by using the electric powersupplied from the high-voltage battery 32 (step S209). In response tothe end of reprogramming (YES in step S211), the DC-DC convertercontroller 60 a causes the DC-DC converter 60 to stop operating (stepS213) and the high-voltage relay controller 34 a breaks the coupling ofthe high-voltage relay 34 (step S215). The process then ends.

On the other hand, if the update-target device 44 subjected toreprogramming is the certain device used for supplying electric powerfrom the high-voltage battery 32 (YES in step S207), the low-voltagebattery controller 42 a of the control device 22 determines whethercharging of the low-voltage battery 42 is completed by using electricpower output from the high-voltage battery 32 (step S217). In oneexample, the low-voltage battery controller 42 a determines whether thecharge level of the low-voltage battery 42 is higher than or equal tothe charge level determined on the basis of the electric power forreprogramming of the update-target device 44 calculated by thehigh-voltage battery controller 32 a.

If it is determined that charging of the low-voltage battery 42 iscompleted (YES in step S217), the DC-DC converter controller 60 a of thecontrol device 22 causes the DC-DC converter 60 to stop operating (stepS219) and the high-voltage relay controller 34 a breaks the coupling ofthe high-voltage relay 34 (step S221).

After the coupling of the high-voltage relay 34 is broken in step S221or if it is determined in step S201 that reprogramming can be performedby using the low-voltage battery 42 (YES in step S201), the controldevice 22 instructs the updater 46 to perform reprogramming. The updater46 performs reprogramming of the update-target device 44 by usingelectric power supplied from the low-voltage battery 42 (step S223). Ifreprogramming ends (YES in step S225), the process ends.

The control method of the reprogramming process performed in the vehicle1 according to the embodiment has been described above. The embodimentprovides the following beneficial effects.

In the related art, electric power used when reprogramming is performedis commonly supplied by the low-voltage battery 42. However, forexample, when the SOC of the low-voltage battery is low, electric powerused for reprogramming may be deficient. If reprogramming is abortedbecause of a deficiency of electric power, this may adversely affect thenormal operation of the vehicle 1, which may lead to replacement of theupdate-target device 44 subjected to reprogramming according tocircumstances.

On the other hand, in the case where reprogramming data is received viawireless communication and reprogramming is performed on the basis ofthe received reprogramming data, if the vehicle 1 is coupled to anexternal power supply with a cable, the convenience is reduced. Thus, itis not desirable to supply electric power from an external power supplywhen reprogramming is performed.

Accordingly, it is conceivable to reduce in voltage the output power ofthe high-voltage battery 32 and use the output power reduced in voltagein reprogramming when electric power of the low-voltage battery 42 usedin reprogramming is deficient in an electric-powered vehicle equippedwith the high-voltage battery 32 for driving the motor. However, in sucha case, it is difficult to perform reprogramming of a certain devicerelating to electric power supply from the high-voltage battery 32 tothe low-voltage system circuit 40.

Accordingly, in the present embodiment, it is determined whether theupdate-target device 44 is a certain device relating to electric powersupply from the high-voltage battery 32 to the low-voltage systemcircuit 40. If it is determined that the update-target device 44 is thecertain device, the DC-DC converter 60 is caused to reduce in voltagethe output electric power of the high-voltage battery 32 and to supplythe electric power reduced in voltage to the low-voltage system circuit40, so that the low-voltage battery 42 is charged. After the low-voltagebattery 42 is charged, the certain device is caused to stop operating.The updater 46 is then caused to perform reprogramming of the certaindevice by using the output electric power of the low-voltage battery 42.Consequently, the likelihood of updating of a program being abortedbecause of a deficiency of electric power can be reduced, andreprogramming of the certain device relating to electric power supplyfrom the high-voltage battery 32 to the low-voltage system circuit 40can be performed.

If it is determined that the update-target device 44 is not the certaindevice, the DC-DC converter 60 is caused to reduce in voltage the outputelectric power of the high-voltage battery 32 and to supply the electricpower reduced in voltage to the low-voltage system circuit 40, and theupdater 46 is caused to update the program of the update-target device44 by using the output electric power of the high-voltage battery 32.Consequently, if the update-target device 44 is not the certain device,charging of the low-voltage battery 42 is omitted. Thus, the time takenfor reprogramming can be reduced.

As described above, the control device 22 determines whether the chargelevel of the low-voltage battery 42 is higher than or equal to theelectric power level used for reprogramming of the update-target device44. If the control device 22 determines that the charge level of thelow-voltage battery 42 is not deficient relative to the electric powerlevel used for reprogramming, the control device 22 causes the updater46 to perform reprogramming of the certain device by using the outputelectric power of the low-voltage battery 42. On the other hand, if thecontrol device 22 determines that the charge level of the low-voltagebattery 42 is deficient relative to the electric power level used forreprogramming, the control device 22 determines whether theupdate-target device 44 is the certain device relating to electric powersupply from the high-voltage battery 32 to the low-voltage systemcircuit 40. Thus, if the charge level of the low-voltage battery 42 ishigher than or equal to the electric power level used for reprogrammingof the update-target device 44, charging of the low-voltage battery 42is omitted. Consequently, the time taken for reprogramming can bereduced.

The embodiment of the disclosure has been described above with referenceto the accompanying drawings. It is needless to say that the disclosureis not limited to such an embodiment. It is obvious that a personskilled in the art can conceive various alterations and modificationswithin a scope of the claims. It is to be understood that thesealterations and modifications are, of course, included in the technicalscope of the disclosure.

In the embodiment described above, reprogramming is started upon theuser's confirmation to perform reprogramming. However, the disclosure isnot limited to this. For example, when the user confirms reprogramming,the user may designate any timing at which reprogramming is actuallyperformed. In this case, when the current time reaches the timing set bythe user, the updater 46 starts reprogramming. If reprogramming is notto be performed because the vehicle 1 is traveling or the like when thecurrent time reaches the timing set by the user, the reprogrammingconfirmation screen 24 a may be displayed again to ask for the user'sconfirmation after the vehicle 1 is stopped.

In the embodiment described above, in the case where the reprogramminginformation is received and reprogramming is scheduled, the high-voltagebattery controller 32 a changes the target SOC lower-limit value of thehigh-voltage battery 32 to a value (scheduled reprogramming preparationvalue) that is higher than the normal value and sets the SOC upper-limitvalue to the normal value. However, the disclosure is not limited tosuch an example. The high-voltage battery controller 32 a may change thetarget SOC upper-limit value of the high-voltage battery 32 to a valuethat is higher than the normal value and also change the target SOClower-limit value of the high-voltage battery 32 to a value (scheduledreprogramming preparation value) that is higher than the normal value.

In the embodiment described above, the case where the vehicle 1 is aparallel hybrid vehicle has been described. However, the disclosure isnot limited to this. The disclosure is applicable to various vehiclessuch as an EV, a plug-in hybrid vehicle (PHEV), and a non-plug-in hybridvehicle (hybrid vehicle).

The control device 22 illustrated in FIG. 1 and the updater 46illustrated in FIG. 2 can be implemented by circuitry including at leastone semiconductor integrated circuit such as at least one processor(e.g., a central processing unit (CPU)), at least one applicationspecific integrated circuit (ASIC), and/or at least one fieldprogrammable gate array (FPGA). At least one processor can beconfigured, by reading instructions from at least one machine readabletangible medium, to perform all or a part of functions of the controldevice 22 including the high-voltage battery controller 32 a, thehigh-voltage relay controller 34 a, the low-voltage battery controller42 a, the automotive navigation system controller 52 a, the IG powersupply controller 54 a, and the DC-DC converter controller 60 a and toperform all or a part of functions of the updater 46. Such a medium maytake many forms, including, but not limited to, any type of magneticmedium such as a hard disk, any type of optical medium such as a CD anda DVD, any type of semiconductor memory (i.e., semiconductor circuit)such as a volatile memory and a non-volatile memory. The volatile memorymay include a DRAM and a SRAM, and the non-volatile memory may include aROM and an NVRAM. The ASIC is an integrated circuit (IC) customized toperform, and the FPGA is an integrated circuit designed to be configuredafter manufacturing in order to perform, all or a part of the functionsof the modules illustrated in FIGS. 1 and 2.

1. A vehicle comprising: a high-voltage system circuit comprising ahigh-voltage battery; a low-voltage system circuit comprising alow-voltage battery having a lower output voltage than the high-voltagebattery, and an updater configured to update a program of anupdate-target device by using electric power supplied from thelow-voltage battery or the high-voltage battery; a direct current(DC)-DC converter coupled between the high-voltage system circuit andthe low-voltage system circuit and capable of reducing in voltage outputelectric power of the high-voltage battery and supplying the electricpower reduced in voltage to the low-voltage system circuit; a controllerconfigured to control the high-voltage system circuit, the low-voltagesystem circuit, and the DC-DC converter, wherein the controller isconfigured to: determine whether the update-target device is a certaindevice relating to electric power supply from the high-voltage batteryto the low-voltage system circuit; and in a case where the update-targetdevice is the certain device, cause the DC-DC converter to reduce involtage the output electric power of the high-voltage battery and tosupply the electric power reduced in voltage to the low-voltage systemcircuit so as to charge the low-voltage battery, cause the certaindevice to stop operating after the low-voltage battery is charged, andcause the updater to update the program of the certain device by usingthe output electric power of the low-voltage battery.
 2. The vehicleaccording to claim 1, wherein the controller is configured to, in a casewhere the update-target device is not the certain device, cause theDC-DC converter to reduce in voltage the output electric power of thehigh-voltage battery and to supply the electric power reduced in voltageto the low-voltage system circuit, and cause the updater to update theprogram of the update-target device by using the output electric powerof the high-voltage battery.
 3. The vehicle according to claim 1,further comprising: a wireless communication device configured towirelessly communicate with an external device, wherein the controlleris configured to: in a case where the wireless communication devicereceives update data for updating the program of the update-targetdevice, calculate, based on information on the update data, electricpower used for updating the program of the update-target device, anddetermine whether a charge level of the low-voltage battery is deficientrelative to the calculated electric power; in a case of determining thatthe charge level of the low-voltage battery is not deficient relative tothe calculated electric power, cause the updater to update the programof the update-target device by using the output electric power of thelow-voltage battery; and in a case of determining that the charge levelof the low-voltage battery is deficient relative to the calculatedelectric power, determine whether the update-target device is thecertain device relating to electric power supply from the high-voltagebattery to the low-voltage system circuit.
 4. The vehicle according toclaim 2, further comprising: a wireless communication device configuredto wirelessly communicate with an external device, wherein thecontroller is configured to: in a case where the wireless communicationdevice receives update data for updating the program of theupdate-target device, calculate, based on information on the updatedata, electric power used for updating the program of the update-targetdevice, and determine whether a charge level of the low-voltage batteryis deficient relative to the calculated electric power; in a case ofdetermining that the charge level of the low-voltage battery is notdeficient relative to the calculated electric power, cause the updaterto update the program of the update-target device by using the outputelectric power of the low-voltage battery; and in a case of determiningthat the charge level of the low-voltage battery is deficient relativeto the calculated electric power, determine whether the update-targetdevice is the certain device relating to electric power supply from thehigh-voltage battery to the low-voltage system circuit.
 5. The vehicleaccording to claim 1, wherein the controller comprises a high-voltagebattery controller configured to control the high-voltage battery, and aDC-DC converter controller configured to control the DC-DC converter,and wherein the certain device includes at least either one of thehigh-voltage battery controller and the DC-DC converter controller. 6.The vehicle according to claim 2, wherein the controller comprises ahigh-voltage battery controller configured to control the high-voltagebattery, and a DC-DC converter controller configured to control theDC-DC converter, and wherein the certain device includes at least eitherone of the high-voltage battery controller and the DC-DC convertercontroller.
 7. The vehicle according to claim 3, wherein the controllercomprises a high-voltage battery controller configured to control thehigh-voltage battery, and a DC-DC converter controller configured tocontrol the DC-DC converter, and wherein the certain device includes atleast either one of the high-voltage battery controller and the DC-DCconverter controller.
 8. The vehicle according to claim 4, wherein thecontroller comprises a high-voltage battery controller configured tocontrol the high-voltage battery, and a DC-DC converter controllerconfigured to control the DC-DC converter, and wherein the certaindevice includes at least either one of the high-voltage batterycontroller and the DC-DC converter controller.
 9. The vehicle accordingto claim 1, further comprising: an engine configured to serve as adriving source for traveling; and a motor coupled to the high-voltagebattery and configured to serve as a driving source for traveling. 10.The vehicle according to claim 2, further comprising: an engineconfigured to serve as a driving source for traveling; and a motorcoupled to the high-voltage battery and configured to serve as a drivingsource for traveling.
 11. The vehicle according to claim 3, furthercomprising: an engine configured to serve as a driving source fortraveling; and a motor coupled to the high-voltage battery andconfigured to serve as a driving source for traveling.
 12. The vehicleaccording to claim 4, further comprising: an engine configured to serveas a driving source for traveling; and a motor coupled to thehigh-voltage battery and configured to serve as a driving source fortraveling.
 13. The vehicle according to claim 5, further comprising: anengine configured to serve as a driving source for traveling; and amotor coupled to the high-voltage battery and configured to serve as adriving source for traveling.
 14. The vehicle according to claim 6,further comprising: an engine configured to serve as a driving sourcefor traveling; and a motor coupled to the high-voltage battery andconfigured to serve as a driving source for traveling.
 15. The vehicleaccording to claim 7, further comprising: an engine configured to serveas a driving source for traveling; and a motor coupled to thehigh-voltage battery and configured to serve as a driving source fortraveling.
 16. The vehicle according to claim 8, further comprising: anengine configured to serve as a driving source for traveling; and amotor coupled to the high-voltage battery and configured to serve as adriving source for traveling.